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Boshchenko AA, Maslov LN, Mukhomedzyanov AV, Zhuravleva OA, Slidnevskaya AS, Naryzhnaya NV, Zinovieva AS, Ilinykh PA. Peptides Are Cardioprotective Drugs of the Future: The Receptor and Signaling Mechanisms of the Cardioprotective Effect of Glucagon-like Peptide-1 Receptor Agonists. Int J Mol Sci 2024; 25:4900. [PMID: 38732142 PMCID: PMC11084666 DOI: 10.3390/ijms25094900] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Revised: 04/10/2024] [Accepted: 04/14/2024] [Indexed: 05/13/2024] Open
Abstract
The high mortality rate among patients with acute myocardial infarction (AMI) is one of the main problems of modern cardiology. It is quite obvious that there is an urgent need to create more effective drugs for the treatment of AMI than those currently used in the clinic. Such drugs could be enzyme-resistant peptide analogs of glucagon-like peptide-1 (GLP-1). GLP-1 receptor (GLP1R) agonists can prevent ischemia/reperfusion (I/R) cardiac injury. In addition, chronic administration of GLP1R agonists can alleviate the development of adverse cardiac remodeling in myocardial infarction, hypertension, and diabetes mellitus. GLP1R agonists can protect the heart against oxidative stress and reduce proinflammatory cytokine (IL-1β, TNF-α, IL-6, and MCP-1) expression in the myocardium. GLP1R stimulation inhibits apoptosis, necroptosis, pyroptosis, and ferroptosis of cardiomyocytes. The activation of the GLP1R augments autophagy and mitophagy in the myocardium. GLP1R agonists downregulate reactive species generation through the activation of Epac and the GLP1R/PI3K/Akt/survivin pathway. The GLP1R, kinases (PKCε, PKA, Akt, AMPK, PI3K, ERK1/2, mTOR, GSK-3β, PKG, MEK1/2, and MKK3), enzymes (HO-1 and eNOS), transcription factors (STAT3, CREB, Nrf2, and FoxO3), KATP channel opening, and MPT pore closing are involved in the cardioprotective effect of GLP1R agonists.
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Affiliation(s)
- Alla A. Boshchenko
- Department of Atherosclerosis and Chronic Coronary Heart Disease, Cardiology Research Institute, Tomsk National Research Medical Center, Russian Academy of Sciences, 634012 Tomsk, Russia
| | - Leonid N. Maslov
- Laboratory of Experimental Cardiology, Cardiology Research Institute, Tomsk National Research Medical Center, Russian Academy of Sciences, 634012 Tomsk, Russia
| | - Alexander V. Mukhomedzyanov
- Laboratory of Experimental Cardiology, Cardiology Research Institute, Tomsk National Research Medical Center, Russian Academy of Sciences, 634012 Tomsk, Russia
| | - Olga A. Zhuravleva
- Department of Atherosclerosis and Chronic Coronary Heart Disease, Cardiology Research Institute, Tomsk National Research Medical Center, Russian Academy of Sciences, 634012 Tomsk, Russia
| | - Alisa S. Slidnevskaya
- Laboratory of Experimental Cardiology, Cardiology Research Institute, Tomsk National Research Medical Center, Russian Academy of Sciences, 634012 Tomsk, Russia
| | - Natalia V. Naryzhnaya
- Laboratory of Experimental Cardiology, Cardiology Research Institute, Tomsk National Research Medical Center, Russian Academy of Sciences, 634012 Tomsk, Russia
| | - Arina S. Zinovieva
- Department of Atherosclerosis and Chronic Coronary Heart Disease, Cardiology Research Institute, Tomsk National Research Medical Center, Russian Academy of Sciences, 634012 Tomsk, Russia
| | - Philipp A. Ilinykh
- Department of Pathology, The University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA
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Qiao L, Lu C, Zang T, Dzyuba B, Shao J. Maternal GLP-1 receptor activation inhibits fetal growth. Am J Physiol Endocrinol Metab 2024; 326:E268-E276. [PMID: 38197791 PMCID: PMC11193516 DOI: 10.1152/ajpendo.00361.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 01/03/2024] [Accepted: 01/03/2024] [Indexed: 01/11/2024]
Abstract
Glucagon-like peptide 1 (GLP-1) regulates food intake, insulin production, and metabolism. Our recent study demonstrated that pancreatic α-cells-secreted (intraislet) GLP-1 effectively promotes maternal insulin secretion and metabolic adaptation during pregnancy. However, the role of circulating GLP-1 in maternal energy metabolism remains largely unknown. Our study aims to investigate systemic GLP-1 response to pregnancy and its regulatory effect on fetal growth. Using C57BL/6 mice, we observed a gradual decline in maternal blood GLP-1 concentrations. Subsequent administration of the GLP-1 receptor agonist semaglutide (Sem) to dams in late pregnancy revealed a modest decrease in maternal food intake during initial treatment. At the same time, no significant alterations were observed in maternal body weight or fat mass. Notably, Sem-treated dams exhibited a significant decrease in fetal body weight, which persisted even following the restoration of maternal blood glucose levels. Despite no observable change in placental weight, a marked reduction in the placenta labyrinth area from Sem-treated dams was evident. Our investigation further demonstrated a substantial decrease in the expression levels of various pivotal nutrient transporters within the placenta, including glucose transporter one and sodium-neutral amino acid transporter one, after Sem treatment. In addition, Sem injection led to a notable reduction in the capillary area, number, and surface densities within the labyrinth. These findings underscore the crucial role of modulating circulating GLP-1 levels in maternal adaptation, emphasizing the inhibitory effects of excessive GLP-1 receptor activation on both placental development and fetal growth.NEW & NOTEWORTHY Our study reveals a progressive decline in maternal blood glucagon-like peptide 1 (GLP-1) concentration. GLP-1 receptor agonist injection in late pregnancy significantly reduced fetal body weight, even after restoration of maternal blood glucose concentration. GLP-1 receptor activation significantly reduced the placental labyrinth area, expression of some nutrient transporters, and capillary development. Our study indicates that reducing maternal blood GLP-1 levels is a physiological adaptation process that benefits placental development and fetal growth.
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Affiliation(s)
- Liping Qiao
- Department of Pediatrics, University of California San Diego, La Jolla, California, United States
| | - Cindy Lu
- Department of Pediatrics, University of California San Diego, La Jolla, California, United States
| | - Tianyi Zang
- Department of Pediatrics, University of California San Diego, La Jolla, California, United States
| | - Brianna Dzyuba
- Department of Pediatrics, University of California San Diego, La Jolla, California, United States
| | - Jianhua Shao
- Department of Pediatrics, University of California San Diego, La Jolla, California, United States
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Anti-Inflammatory Effects of GLP-1 Receptor Activation in the Brain in Neurodegenerative Diseases. Int J Mol Sci 2022; 23:ijms23179583. [PMID: 36076972 PMCID: PMC9455625 DOI: 10.3390/ijms23179583] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 08/17/2022] [Accepted: 08/21/2022] [Indexed: 11/16/2022] Open
Abstract
The glucagon-like peptide-1 (GLP-1) is a pleiotropic hormone well known for its incretin effect in the glucose-dependent stimulation of insulin secretion. However, GLP-1 is also produced in the brain and displays a critical role in neuroprotection and inflammation by activating the GLP-1 receptor signaling pathways. Several studies in vivo and in vitro using preclinical models of neurodegenerative diseases show that GLP-1R activation has anti-inflammatory properties. This review explores the molecular mechanistic action of GLP-1 RAS in relation to inflammation in the brain. These findings update our knowledge of the potential benefits of GLP-1RAS actions in reducing the inflammatory response. These molecules emerge as a potential therapeutic tool in treating neurodegenerative diseases and neuroinflammatory pathologies.
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Fernandes MF, Tomczewski MV, Duncan RE. Glucagon-like Peptide-1 Secretion Is Inhibited by Lysophosphatidic Acid. Int J Mol Sci 2022; 23:ijms23084163. [PMID: 35456981 PMCID: PMC9025735 DOI: 10.3390/ijms23084163] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 04/07/2022] [Accepted: 04/08/2022] [Indexed: 12/27/2022] Open
Abstract
Glucagon-like peptide-1 (GLP-1) potentiates glucose-stimulated insulin secretion (GSIS). While dozens of compounds stimulate GLP-1 secretion, few inhibit. Reduced GLP-1 secretion and impaired GSIS occur in chronic inflammation. Lysophosphatidic acids (LPAs) are bioactive phospholipids elevated in inflammation. The aim of this study was to test whether LPA inhibits GLP-1 secretion in vitro and in vivo. GLUTag L-cells were treated with various LPA species, with or without LPA receptor (LPAR) antagonists, and media GLP-1 levels, cellular cyclic AMP and calcium ion concentrations, and DPP4 activity levels were analyzed. Mice were injected with LPA, with or without LPAR antagonists, and serum GLP-1 and DPP4 activity were measured. GLUTag GLP-1 secretion was decreased ~70–90% by various LPAs. GLUTag expression of Lpar1, 2, and 3 was orders of magnitude higher than Lpar4, 5, and 6, implicating the former group in this effect. In agreement, inhibition of GLP-1 secretion was reversed by the LPAR1/3 antagonist Ki16425, the LPAR1 antagonists AM095 and AM966, or the LPAR2 antagonist LPA2-antagonist 1. We hypothesized involvement of Gαi-mediated LPAR activity, and found that intracellular cyclic AMP and calcium ion concentrations were decreased by LPA, but restored by Ki16425. Mouse LPA injection caused an ~50% fall in circulating GLP-1, although only LPAR1 or LPAR1/3 antagonists, but not LPAR2 antagonism, prevented this. GLUTag L-cell and mouse serum DPP4 activity was unchanged by LPA or LPAR antagonists. LPA therefore impairs GLP-1 secretion in vitro and in vivo through Gαi-coupled LPAR1/3 signaling, providing a new mechanism linking inflammation with impaired GSIS.
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Diz-Chaves Y, Herrera-Pérez S, González-Matías LC, Mallo F. Effects of Glucagon-like peptide 1 (GLP-1) analogs in the hippocampus. VITAMINS AND HORMONES 2022; 118:457-478. [PMID: 35180937 DOI: 10.1016/bs.vh.2021.12.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
The glucagon-like peptide-1 (GLP-1) is a pleiotropic hormone very well known for its incretin effect in the glucose-dependent stimulation of insulin secretion. However, GLP-1 is also produced in the brain, and it displays critical roles in neuroprotection by activating the GLP-1 receptor signaling pathways. GLP-1 enhances learning and memory in the hippocampus, promotes neurogenesis, decreases inflammation and apoptosis, modulates reward behavior, and reduces food intake. Its pharmacokinetics have been improved to enhance the peptide's half-life, enhancing exposure and time of action. The GLP-1 agonists are successfully in clinical use for the treatment of type-2 diabetes, obesity, and clinical evaluation for the treatment of neurodegenerative diseases.
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Affiliation(s)
- Yolanda Diz-Chaves
- Laboratory of Endocrinology, Biomedical Research Center (CINBIO), University of Vigo, Vigo, Spain.
| | - Salvador Herrera-Pérez
- Laboratory of Neuroscience, Biomedical Research Center (CINBIO), University of Vigo, Vigo, Spain
| | - Lucas C González-Matías
- Laboratory of Endocrinology, Biomedical Research Center (CINBIO), University of Vigo, Vigo, Spain
| | - Federico Mallo
- Laboratory of Endocrinology, Biomedical Research Center (CINBIO), University of Vigo, Vigo, Spain
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London E, Stratakis CA. The regulation of PKA signaling in obesity and in the maintenance of metabolic health. Pharmacol Ther 2022; 237:108113. [PMID: 35051439 DOI: 10.1016/j.pharmthera.2022.108113] [Citation(s) in RCA: 34] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 01/03/2022] [Accepted: 01/11/2022] [Indexed: 12/13/2022]
Abstract
The cAMP-dependent protein kinase (PKA) system represents a primary cell-signaling pathway throughout systems and across species. PKA facilitates the actions of hormones, neurotransmitters and other signaling molecules that bind G-protein coupled receptors (GPCR) to modulate cAMP levels. Through its control of synaptic events, exocytosis, transcriptional regulation, and more, PKA signaling regulates cellular metabolism and emotional and stress responses making it integral in the maintenance and dysregulation of energy homeostasis. Neural PKA signaling is regulated by afferent and peripheral efferent signals that link specific neural cell populations to the regulation of metabolic processes in adipose tissue, liver, pancreas, adrenal, skeletal muscle, and gut. Mouse models have provided invaluable information on the roles for PKA subunits in brain and key metabolic organs. While limited, human studies infer differential regulation of the PKA system in obese compared to lean individuals. Variants identified in PKA subunit genes cause Cushing syndrome that is characterized by metabolic dysregulation associated with endogenous glucocorticoid excess. Under healthy physiologic conditions, the PKA system is exquisitely regulated by stimuli that activate GPCRs to alter intracellular cAMP concentrations, and by PKA cellular localization and holoenzyme stability. Adenylate cyclase activity generates cAMP while phosphodiesterase-mediated cAMP degradation to AMP decreases cAMP levels downstream of GPCRs. Chronic perturbations in PKA signaling appear to be capable of resetting PKA regulation at several levels; in addition, sex differences in PKA signaling regulation, while not well understood, impact the physiologic consequences of metabolic dysregulation and obesity. This review explores the roles for PKA signaling in the pathogenesis of metabolic diseases including obesity, type 2 diabetes mellitus and associated co-morbidities through neural-peripheral crosstalk and cAMP/PKA signaling pathway targets that hold therapeutic potential.
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Affiliation(s)
- Edra London
- Section on Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, USA.
| | - Constantine A Stratakis
- Section on Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, USA; Human Genetics & Precision Medicine, IMBB, Foundation for Research & Technology Hellas, Greece; Research Institute, ELPEN, SA, Athens, Greece
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Bethea M, Bozadjieva-Kramer N, Sandoval DA. Preproglucagon Products and Their Respective Roles Regulating Insulin Secretion. Endocrinology 2021; 162:6329397. [PMID: 34318874 PMCID: PMC8375443 DOI: 10.1210/endocr/bqab150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Indexed: 11/19/2022]
Abstract
Historically, intracellular function and metabolic adaptation within the α-cell has been understudied, with most of the attention being placed on the insulin-producing β-cells due to their role in the pathophysiology of type 2 diabetes mellitus. However, there is a growing interest in understanding the function of other endocrine cell types within the islet and their paracrine role in regulating insulin secretion. For example, there is greater appreciation for α-cell products and their contributions to overall glucose homeostasis. Several recent studies have addressed a paracrine role for α-cell-derived glucagon-like peptide-1 (GLP-1) in regulating glucose homeostasis and responses to metabolic stress. Further, other studies have demonstrated the ability of glucagon to impact insulin secretion by acting through the GLP-1 receptor. These studies challenge the central dogma surrounding α-cell biology describing glucagon's primary role in glucose counterregulation to one where glucagon is critical in regulating both hyper- and hypoglycemic responses. Herein, this review will update the current understanding of the role of glucagon and α-cell-derived GLP-1, placing emphasis on their roles in regulating glucose homeostasis, insulin secretion, and β-cell mass.
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Affiliation(s)
- Maigen Bethea
- Department of Pediatrics, Nutrition Section, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
- Division of Endocrinology, Metabolism, and Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | | | - Darleen A Sandoval
- Department of Pediatrics, Nutrition Section, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
- Division of Endocrinology, Metabolism, and Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
- Correspondence: Darleen A. Sandoval, PhD, University of Colorado Anschut, Division of Endocrinology, Metabolism, and Diabetes,12801 E 17th Ave. Research Complex 1 South 7th Floor, Aurora, CO 80045, USA. E-mail:
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8
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Zeigerer A, Sekar R, Kleinert M, Nason S, Habegger KM, Müller TD. Glucagon's Metabolic Action in Health and Disease. Compr Physiol 2021; 11:1759-1783. [PMID: 33792899 PMCID: PMC8513137 DOI: 10.1002/cphy.c200013] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Discovered almost simultaneously with insulin, glucagon is a pleiotropic hormone with metabolic action that goes far beyond its classical role to increase blood glucose. Albeit best known for its ability to directly act on the liver to increase de novo glucose production and to inhibit glycogen breakdown, glucagon lowers body weight by decreasing food intake and by increasing metabolic rate. Glucagon further promotes lipolysis and lipid oxidation and has positive chronotropic and inotropic effects in the heart. Interestingly, recent decades have witnessed a remarkable renaissance of glucagon's biology with the acknowledgment that glucagon has pharmacological value beyond its classical use as rescue medication to treat severe hypoglycemia. In this article, we summarize the multifaceted nature of glucagon with a special focus on its hepatic action and discuss the pharmacological potential of either agonizing or antagonizing the glucagon receptor for health and disease. © 2021 American Physiological Society. Compr Physiol 11:1759-1783, 2021.
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Affiliation(s)
- Anja Zeigerer
- Institute for Diabetes and Cancer, Helmholtz Center Munich, Neuherberg, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Revathi Sekar
- Institute for Diabetes and Cancer, Helmholtz Center Munich, Neuherberg, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Maximilian Kleinert
- German Center for Diabetes Research (DZD), Neuherberg, Germany
- Institute for Diabetes and Obesity, Helmholtz Center Munich, Neuherberg, Germany
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Shelly Nason
- Comprehensive Diabetes Center, Department of Medicine - Endocrinology, Diabetes & Metabolism, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Kirk M. Habegger
- Comprehensive Diabetes Center, Department of Medicine - Endocrinology, Diabetes & Metabolism, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Timo D. Müller
- German Center for Diabetes Research (DZD), Neuherberg, Germany
- Institute for Diabetes and Obesity, Helmholtz Center Munich, Neuherberg, Germany
- Department of Pharmacology, Experimental Therapy and Toxicology, Institute of Experimental and Clinical Pharmacology and Pharmacogenomics, Eberhard Karls University Hospitals and Clinics, Tübingen, Germany
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Schalla MA, Taché Y, Stengel A. Neuroendocrine Peptides of the Gut and Their Role in the Regulation of Food Intake. Compr Physiol 2021; 11:1679-1730. [PMID: 33792904 DOI: 10.1002/cphy.c200007] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The regulation of food intake encompasses complex interplays between the gut and the brain. Among them, the gastrointestinal tract releases different peptides that communicate the metabolic state to specific nuclei in the hindbrain and the hypothalamus. The present overview gives emphasis on seven peptides that are produced by and secreted from specialized enteroendocrine cells along the gastrointestinal tract in relation with the nutritional status. These established modulators of feeding are ghrelin and nesfatin-1 secreted from gastric X/A-like cells, cholecystokinin (CCK) secreted from duodenal I-cells, glucagon-like peptide 1 (GLP-1), oxyntomodulin, and peptide YY (PYY) secreted from intestinal L-cells and uroguanylin (UGN) released from enterochromaffin (EC) cells. © 2021 American Physiological Society. Compr Physiol 11:1679-1730, 2021.
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Affiliation(s)
- Martha A Schalla
- Charité Center for Internal Medicine and Dermatology, Department for Psychosomatic Medicine, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Berlin, Germany
| | - Yvette Taché
- Vatche and Tamar Manoukian Division of Digestive Diseases, Department of Medicine, CURE: Digestive Diseases Research Center, David Geffen School of Medicine, UCLA, Los Angeles, California, USA.,VA Greater Los Angeles Healthcare System, Los Angeles, California, USA
| | - Andreas Stengel
- Charité Center for Internal Medicine and Dermatology, Department for Psychosomatic Medicine, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Berlin, Germany.,Department of Psychosomatic Medicine and Psychotherapy, Medical University Hospital Tübingen, Tübingen, Germany
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Alhabeeb H, AlFaiz A, Kutbi E, AlShahrani D, Alsuhail A, AlRajhi S, Alotaibi N, Alotaibi K, AlAmri S, Alghamdi S, AlJohani N. Gut Hormones in Health and Obesity: The Upcoming Role of Short Chain Fatty Acids. Nutrients 2021; 13:nu13020481. [PMID: 33572661 PMCID: PMC7911102 DOI: 10.3390/nu13020481] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Revised: 12/21/2020] [Accepted: 12/30/2020] [Indexed: 12/13/2022] Open
Abstract
We are currently facing an obesity pandemic, with worldwide obesity rates having tripled since 1975. Obesity is one of the main risk factors for the development of non-communicable diseases, which are now the leading cause of death worldwide. This calls for urgent action towards understanding the underlying mechanisms behind the development of obesity as well as developing more effective treatments and interventions. Appetite is carefully regulated in humans via the interaction between the central nervous system and peripheral hormones. This involves a delicate balance in external stimuli, circulating satiating and appetite stimulating hormones, and correct functioning of neuronal signals. Any changes in this equilibrium can lead to an imbalance in energy intake versus expenditure, which often leads to overeating, and potentially weight gain resulting in overweight or obesity. Several lines of research have shown imbalances in gut hormones are found in those who are overweight or obese, which may be contributing to their condition. Therefore, this review examines the evidence for targeting gut hormones in the treatment of obesity by discussing how their dysregulation influences food intake, the potential possibility of altering the circulating levels of these hormones for treating obesity, as well as the role of short chain fatty acids and protein as novel treatments.
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Affiliation(s)
- Habeeb Alhabeeb
- Research Center, King Fahad Medical City—KFMC, Riyadh 11525, Saudi Arabia; (A.A.); (E.K.); (D.A.); (A.A.); (S.A.); (S.A.)
- Correspondence:
| | - Ali AlFaiz
- Research Center, King Fahad Medical City—KFMC, Riyadh 11525, Saudi Arabia; (A.A.); (E.K.); (D.A.); (A.A.); (S.A.); (S.A.)
| | - Emad Kutbi
- Research Center, King Fahad Medical City—KFMC, Riyadh 11525, Saudi Arabia; (A.A.); (E.K.); (D.A.); (A.A.); (S.A.); (S.A.)
| | - Dayel AlShahrani
- Research Center, King Fahad Medical City—KFMC, Riyadh 11525, Saudi Arabia; (A.A.); (E.K.); (D.A.); (A.A.); (S.A.); (S.A.)
| | - Abdullah Alsuhail
- Research Center, King Fahad Medical City—KFMC, Riyadh 11525, Saudi Arabia; (A.A.); (E.K.); (D.A.); (A.A.); (S.A.); (S.A.)
| | - Saleh AlRajhi
- Family Medicine, King Fahad Medical City—KFMC, Riyadh 11525, Saudi Arabia;
| | - Nemer Alotaibi
- College of Medicine, Shaqra University, Shaqra 11961, Saudi Arabia; (N.A.); (K.A.)
| | - Khalid Alotaibi
- College of Medicine, Shaqra University, Shaqra 11961, Saudi Arabia; (N.A.); (K.A.)
| | - Saad AlAmri
- Research Center, King Fahad Medical City—KFMC, Riyadh 11525, Saudi Arabia; (A.A.); (E.K.); (D.A.); (A.A.); (S.A.); (S.A.)
| | - Saleh Alghamdi
- Research Center, King Fahad Medical City—KFMC, Riyadh 11525, Saudi Arabia; (A.A.); (E.K.); (D.A.); (A.A.); (S.A.); (S.A.)
| | - Naji AlJohani
- Obesity, Endocrine, and Metabolism Center, King Fahad Medical City—KFMC, Riyadh 11525, Saudi Arabia;
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Pereira de Arruda EH, Vieira da Silva GL, da Rosa-Santos CA, Arantes VC, de Barros Reis MA, Colodel EM, Gaspar de Moura E, Lisboa PC, Carneiro EM, Damazo AS, Latorraca MQ. Protein restriction during pregnancy impairs intra-islet GLP-1 and the expansion of β-cell mass. Mol Cell Endocrinol 2020; 518:110977. [PMID: 32791189 DOI: 10.1016/j.mce.2020.110977] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2020] [Revised: 07/14/2020] [Accepted: 08/03/2020] [Indexed: 12/26/2022]
Abstract
We evaluated whether protein restriction during pregnancy alters the morphometry of pancreatic islets, the intra-islet glucagon-like peptide-1 (GLP-1) production, and the anti-apoptotic signalling pathway modulated by GLP-1. Control non-pregnant (CNP) and control pregnant (CP) rats were fed a 17% protein diet, and low-protein non-pregnant (LPNP) and low-protein pregnant (LPP) groups were fed a 6% protein diet. The masses of islets and β-cells were similar in the LPNP group and the CNP group but were higher in the CP group than in the CNP group and were equal in the LPP group and the LPNP group. Both variables were lower in the LPP group than in the CP group. Prohormone convertase 2 and GLP-1 fluorescence in α-cells was lower in the low-protein groups than in the control groups. The least PC2/glucagon colocalization was observed in the LPP group, and the most was observed in the CP group. There was less prohormone convertase 1/3/glucagon colocalization in the LPP group than in the CP group. GLP-1/glucagon colocalization was similar in the LPP, CP and CNP groups, which showed less GLP-1/glucagon colocalization than the LPNP group. The mRNA Pka, Creb and Pdx-1 contents were higher in islets from pregnant rats than in islets from non-pregnant rats. Protein restriction during pregnancy impaired the mass of β-cells and the intra-islet GLP-1 production but did not interfere with the transcription of genes of the anti-apoptotic signalling pathway modulated by GLP-1.
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Affiliation(s)
| | | | - Chaiane Aline da Rosa-Santos
- Mestrado em Nutrição, Alimentos e Metabolismo, Faculdade de Nutrição, Universidade Federal de Mato Grosso, Cuiabá, MT, Brazil
| | - Vanessa Cristina Arantes
- Departamento de Alimentos e Nutrição, Faculdade de Nutrição, Universidade Federal de Mato Grosso, Cuiabá, MT, Brazil
| | | | - Edson Moleta Colodel
- Departamento de Clínica Médica Veterinária, Faculdade de Agronomia e Medicina Veterinária, Universidade Federal de Mato Grosso, Cuiabá, MT, Brazil
| | - Egberto Gaspar de Moura
- Laboratório de Fisiologia Endócrina, Departamento de Ciências Fisiológicas, Instituto de Biologia, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Patrícia Cristina Lisboa
- Laboratório de Fisiologia Endócrina, Departamento de Ciências Fisiológicas, Instituto de Biologia, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Everardo Magalhães Carneiro
- Departamento de Anatomia, Biologia Cellular, Fisiologia e Biofísica, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, SP, Brazil
| | - Amílcar Sabino Damazo
- Departamento de Ciências Básicas da Saúde, Faculdade de Medicina, Universidade Federal de Mato Grosso, Cuiabá, MT, Brazil
| | - Márcia Queiroz Latorraca
- Departamento de Alimentos e Nutrição, Faculdade de Nutrição, Universidade Federal de Mato Grosso, Cuiabá, MT, Brazil.
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Stemmer K, Finan B, DiMarchi RD, Tschöp MH, Müller TD. Insights into incretin-based therapies for treatment of diabetic dyslipidemia. Adv Drug Deliv Rev 2020; 159:34-53. [PMID: 32485206 DOI: 10.1016/j.addr.2020.05.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 05/09/2020] [Accepted: 05/23/2020] [Indexed: 02/07/2023]
Abstract
Derangements in triglyceride and cholesterol metabolism (dyslipidemia) are major risk factors for the development of cardiovascular diseases in obese and type-2 diabetic (T2D) patients. An emerging class of glucagon-like peptide-1 (GLP-1) analogues and next generation peptide dual-agonists such as GLP-1/glucagon or GLP-1/GIP could provide effective therapeutic options for T2D patients. In addition to their role in glucose and energy homeostasis, GLP-1, GIP and glucagon serve as regulators of lipid metabolism. This review summarizes the current knowledge in GLP-1, glucagon and GIP effects on lipid and lipoprotein metabolism and frames the emerging therapeutic benefits of GLP-1 analogs and GLP-1-based multiagonists as add-on treatment options for diabetes associated dyslipidemia.
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Davis EM, Sandoval DA. Glucagon‐Like Peptide‐1: Actions and Influence on Pancreatic Hormone Function. Compr Physiol 2020; 10:577-595. [DOI: 10.1002/cphy.c190025] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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14
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Müller TD, Finan B, Bloom SR, D'Alessio D, Drucker DJ, Flatt PR, Fritsche A, Gribble F, Grill HJ, Habener JF, Holst JJ, Langhans W, Meier JJ, Nauck MA, Perez-Tilve D, Pocai A, Reimann F, Sandoval DA, Schwartz TW, Seeley RJ, Stemmer K, Tang-Christensen M, Woods SC, DiMarchi RD, Tschöp MH. Glucagon-like peptide 1 (GLP-1). Mol Metab 2019; 30:72-130. [PMID: 31767182 PMCID: PMC6812410 DOI: 10.1016/j.molmet.2019.09.010] [Citation(s) in RCA: 825] [Impact Index Per Article: 165.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Revised: 09/10/2019] [Accepted: 09/22/2019] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND The glucagon-like peptide-1 (GLP-1) is a multifaceted hormone with broad pharmacological potential. Among the numerous metabolic effects of GLP-1 are the glucose-dependent stimulation of insulin secretion, decrease of gastric emptying, inhibition of food intake, increase of natriuresis and diuresis, and modulation of rodent β-cell proliferation. GLP-1 also has cardio- and neuroprotective effects, decreases inflammation and apoptosis, and has implications for learning and memory, reward behavior, and palatability. Biochemically modified for enhanced potency and sustained action, GLP-1 receptor agonists are successfully in clinical use for the treatment of type-2 diabetes, and several GLP-1-based pharmacotherapies are in clinical evaluation for the treatment of obesity. SCOPE OF REVIEW In this review, we provide a detailed overview on the multifaceted nature of GLP-1 and its pharmacology and discuss its therapeutic implications on various diseases. MAJOR CONCLUSIONS Since its discovery, GLP-1 has emerged as a pleiotropic hormone with a myriad of metabolic functions that go well beyond its classical identification as an incretin hormone. The numerous beneficial effects of GLP-1 render this hormone an interesting candidate for the development of pharmacotherapies to treat obesity, diabetes, and neurodegenerative disorders.
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Affiliation(s)
- T D Müller
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Neuherberg, Germany; German Center for Diabetes Research (DZD), Neuherberg, Germany; Department of Pharmacology and Experimental Therapy, Institute of Experimental and Clinical Pharmacology and Toxicology, Eberhard Karls University Hospitals and Clinics, Tübingen, Germany.
| | - B Finan
- Novo Nordisk Research Center Indianapolis, Indianapolis, IN, USA
| | - S R Bloom
- Division of Diabetes, Endocrinology and Metabolism, Imperial College London, London, UK
| | - D D'Alessio
- Division of Endocrinology, Duke University Medical Center, Durham, NC, USA
| | - D J Drucker
- The Department of Medicine, Lunenfeld-Tanenbaum Research Institute, Mt. Sinai Hospital, University of Toronto, Ontario, M5G1X5, Canada
| | - P R Flatt
- SAAD Centre for Pharmacy & Diabetes, Ulster University, Coleraine, Northern Ireland, UK
| | - A Fritsche
- German Center for Diabetes Research (DZD), Neuherberg, Germany; Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany; Division of Endocrinology, Diabetology, Vascular Disease, Nephrology and Clinical Chemistry, Department of Internal Medicine, University of Tübingen, Tübingen, Germany
| | - F Gribble
- Metabolic Research Laboratories and Medical Research Council Metabolic Diseases Unit, Wellcome Trust-Medical Research Council, Institute of Metabolic Science, Addenbrooke's Hospital, University of Cambridge, Cambridge, CB2 0QQ, UK
| | - H J Grill
- Institute of Diabetes, Obesity and Metabolism, Department of Psychology, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - J F Habener
- Laboratory of Molecular Endocrinology, Massachusetts General Hospital, Harvard University, Boston, MA, USA
| | - J J Holst
- Novo Nordisk Foundation Center for Basic Metabolic Research, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - W Langhans
- Physiology and Behavior Laboratory, ETH Zurich, Schwerzenbach, Switzerland
| | - J J Meier
- Diabetes Division, St Josef Hospital, Ruhr-University Bochum, Bochum, Germany
| | - M A Nauck
- Diabetes Center Bochum-Hattingen, St Josef Hospital (Ruhr-Universität Bochum), Bochum, Germany
| | - D Perez-Tilve
- Department of Internal Medicine, University of Cincinnati-College of Medicine, Cincinnati, OH, USA
| | - A Pocai
- Cardiovascular & ImmunoMetabolism, Janssen Research & Development, Welsh and McKean Roads, Spring House, PA, 19477, USA
| | - F Reimann
- Metabolic Research Laboratories and Medical Research Council Metabolic Diseases Unit, Wellcome Trust-Medical Research Council, Institute of Metabolic Science, Addenbrooke's Hospital, University of Cambridge, Cambridge, CB2 0QQ, UK
| | - D A Sandoval
- Department of Surgery, University of Michigan Medical School, Ann Arbor, MI, USA
| | - T W Schwartz
- Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, DL-2200, Copenhagen, Denmark; Department of Biomedical Sciences, University of Copenhagen, DK-2200, Copenhagen, Denmark
| | - R J Seeley
- Department of Surgery, University of Michigan Medical School, Ann Arbor, MI, USA
| | - K Stemmer
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Neuherberg, Germany; German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - M Tang-Christensen
- Obesity Research, Global Drug Discovery, Novo Nordisk A/S, Måløv, Denmark
| | - S C Woods
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati, Cincinnati, OH, USA
| | - R D DiMarchi
- Novo Nordisk Research Center Indianapolis, Indianapolis, IN, USA; Department of Chemistry, Indiana University, Bloomington, IN, USA
| | - M H Tschöp
- German Center for Diabetes Research (DZD), Neuherberg, Germany; Division of Metabolic Diseases, Department of Medicine, Technische Universität München, Munich, Germany; Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Neuherberg, Germany
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Kanasaki K, Kawakita E, Koya D. Relevance of Autophagy Induction by Gastrointestinal Hormones: Focus on the Incretin-Based Drug Target and Glucagon. Front Pharmacol 2019; 10:476. [PMID: 31156426 PMCID: PMC6531852 DOI: 10.3389/fphar.2019.00476] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Accepted: 04/16/2019] [Indexed: 12/13/2022] Open
Abstract
The biology of autophagy in health and disease conditions has been intensively analyzed for decades. Several potential interventions can induce autophagy in preclinical research; however, none of these interventions are ready for translation to clinical practice yet. The topic of the current review is the molecular regulation of autophagy by glucagon, glucagon-like peptide (GLP)-1 and the GLP-1-degrading enzyme dipeptidyl peptidase-4 (DPP-4). Glucagon is a well-known polypeptide that induces autophagy. In contrast, GLP-1 has been shown to inhibit glucagon secretion; GLP-1 also has been related to the induction of autophagy. DPP-4 inhibitors can induce autophagy in a GLP-1-dependent manner, but other diverse effects could be relevant. Here, we analyze the distinct molecular regulation of autophagy by glucagon, GLP-1, and DPP-4 inhibitors. Additionally, the potential contribution to autophagy by glucagon and GLP-1 after bariatric surgery is discussed.
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Affiliation(s)
- Keizo Kanasaki
- Department of Diabetology and Endocrinology, Kanazawa Medical University, Uchinada, Japan.,Division of Anticipatory Molecular Food Science and Technology, Medical Research Institute, Kanazawa Medical University, Uchinada, Japan
| | - Emi Kawakita
- Department of Diabetology and Endocrinology, Kanazawa Medical University, Uchinada, Japan
| | - Daisuke Koya
- Department of Diabetology and Endocrinology, Kanazawa Medical University, Uchinada, Japan.,Division of Anticipatory Molecular Food Science and Technology, Medical Research Institute, Kanazawa Medical University, Uchinada, Japan
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16
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Traub S, Meier DT, Schulze F, Dror E, Nordmann TM, Goetz N, Koch N, Dalmas E, Stawiski M, Makshana V, Thorel F, Herrera PL, Böni-Schnetzler M, Donath MY. Pancreatic α Cell-Derived Glucagon-Related Peptides Are Required for β Cell Adaptation and Glucose Homeostasis. Cell Rep 2017; 18:3192-3203. [PMID: 28355570 DOI: 10.1016/j.celrep.2017.03.005] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Revised: 01/22/2017] [Accepted: 03/01/2017] [Indexed: 02/04/2023] Open
Abstract
Pancreatic α cells may process proglucagon not only to glucagon but also to glucagon-like peptide-1 (GLP-1). However, the biological relevance of paracrine GLP-1 for β cell function remains unclear. We studied effects of locally derived insulin secretagogues on β cell function and glucose homeostasis using mice with α cell ablation and with α cell-specific GLP-1 deficiency. Normally, intestinal GLP-1 compensates for the lack of α cell-derived GLP-1. However, upon aging and metabolic stress, glucose tolerance is impaired. This was partly rescued with the DPP-4 inhibitor sitagliptin, but not with glucagon administration. In isolated islets from these mice, glucose-stimulated insulin secretion was heavily impaired and exogenous GLP-1 or glucagon rescued insulin secretion. These data highlight the importance of α cell-derived GLP-1 for glucose homeostasis during metabolic stress and may impact on the clinical use of systemic GLP-1 agonists versus stabilizing local α cell-derived GLP-1 by DPP-4 inhibitors in type 2 diabetes.
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Affiliation(s)
- Shuyang Traub
- Endocrinology, Diabetes, and Metabolism, University Hospital Basel, 4031 Basel, Switzerland; Department of Biomedicine, University of Basel, 4031 Basel, Switzerland
| | - Daniel T Meier
- Endocrinology, Diabetes, and Metabolism, University Hospital Basel, 4031 Basel, Switzerland; Department of Biomedicine, University of Basel, 4031 Basel, Switzerland
| | - Friederike Schulze
- Endocrinology, Diabetes, and Metabolism, University Hospital Basel, 4031 Basel, Switzerland; Department of Biomedicine, University of Basel, 4031 Basel, Switzerland
| | - Erez Dror
- Endocrinology, Diabetes, and Metabolism, University Hospital Basel, 4031 Basel, Switzerland; Department of Biomedicine, University of Basel, 4031 Basel, Switzerland
| | - Thierry M Nordmann
- Endocrinology, Diabetes, and Metabolism, University Hospital Basel, 4031 Basel, Switzerland; Department of Biomedicine, University of Basel, 4031 Basel, Switzerland
| | - Nicole Goetz
- Endocrinology, Diabetes, and Metabolism, University Hospital Basel, 4031 Basel, Switzerland; Department of Biomedicine, University of Basel, 4031 Basel, Switzerland
| | - Norina Koch
- Endocrinology, Diabetes, and Metabolism, University Hospital Basel, 4031 Basel, Switzerland; Department of Biomedicine, University of Basel, 4031 Basel, Switzerland
| | - Elise Dalmas
- Endocrinology, Diabetes, and Metabolism, University Hospital Basel, 4031 Basel, Switzerland; Department of Biomedicine, University of Basel, 4031 Basel, Switzerland
| | - Marc Stawiski
- Endocrinology, Diabetes, and Metabolism, University Hospital Basel, 4031 Basel, Switzerland; Department of Biomedicine, University of Basel, 4031 Basel, Switzerland
| | - Valmir Makshana
- Endocrinology, Diabetes, and Metabolism, University Hospital Basel, 4031 Basel, Switzerland; Department of Biomedicine, University of Basel, 4031 Basel, Switzerland
| | - Fabrizio Thorel
- Department of Genetic Medicine and Development, Faculty of Medicine, University of Geneva, 1211 Geneva, Switzerland; Institute of Genetics and Genomics in Geneva (iGE3), University of Geneva, 1211 Geneva, Switzerland; Centre facultaire du diabète, University of Geneva, 1211 Geneva, Switzerland
| | - Pedro L Herrera
- Department of Genetic Medicine and Development, Faculty of Medicine, University of Geneva, 1211 Geneva, Switzerland; Institute of Genetics and Genomics in Geneva (iGE3), University of Geneva, 1211 Geneva, Switzerland; Centre facultaire du diabète, University of Geneva, 1211 Geneva, Switzerland
| | - Marianne Böni-Schnetzler
- Endocrinology, Diabetes, and Metabolism, University Hospital Basel, 4031 Basel, Switzerland; Department of Biomedicine, University of Basel, 4031 Basel, Switzerland
| | - Marc Y Donath
- Endocrinology, Diabetes, and Metabolism, University Hospital Basel, 4031 Basel, Switzerland; Department of Biomedicine, University of Basel, 4031 Basel, Switzerland.
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Domenger D, Caron J, Belguesmia Y, Lesage J, Dhulster P, Ravallec R, Cudennec B. Bioactivities of hemorphins released from bovine haemoglobin gastrointestinal digestion: Dual effects on intestinal hormones and DPP-IV regulations. J Funct Foods 2017. [DOI: 10.1016/j.jff.2017.06.047] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Müller TD, Finan B, Clemmensen C, DiMarchi RD, Tschöp MH. The New Biology and Pharmacology of Glucagon. Physiol Rev 2017; 97:721-766. [PMID: 28275047 DOI: 10.1152/physrev.00025.2016] [Citation(s) in RCA: 206] [Impact Index Per Article: 29.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
In the last two decades we have witnessed sizable progress in defining the role of gastrointestinal signals in the control of glucose and energy homeostasis. Specifically, the molecular basis of the huge metabolic benefits in bariatric surgery is emerging while novel incretin-based medicines based on endogenous hormones such as glucagon-like peptide 1 and pancreas-derived amylin are improving diabetes management. These and related developments have fostered the discovery of novel insights into endocrine control of systemic metabolism, and in particular a deeper understanding of the importance of communication across vital organs, and specifically the gut-brain-pancreas-liver network. Paradoxically, the pancreatic peptide glucagon has reemerged in this period among a plethora of newly identified metabolic macromolecules, and new data complement and challenge its historical position as a gut hormone involved in metabolic control. The synthesis of glucagon analogs that are biophysically stable and soluble in aqueous solutions has promoted biological study that has enriched our understanding of glucagon biology and ironically recruited glucagon agonism as a central element to lower body weight in the treatment of metabolic disease. This review summarizes the extensive historical record and the more recent provocative direction that integrates the prominent role of glucagon in glucose elevation with its under-acknowledged effects on lipids, body weight, and vascular health that have implications for the pathophysiology of metabolic diseases, and the emergence of precision medicines to treat metabolic diseases.
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Affiliation(s)
- T D Müller
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany; German Center for Diabetes Research, Neuherberg, Germany; Department of Chemistry, Indiana University, Bloomington, Indiana; Division of Metabolic Diseases, Technische Universität München, Munich, Germany
| | - B Finan
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany; German Center for Diabetes Research, Neuherberg, Germany; Department of Chemistry, Indiana University, Bloomington, Indiana; Division of Metabolic Diseases, Technische Universität München, Munich, Germany
| | - C Clemmensen
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany; German Center for Diabetes Research, Neuherberg, Germany; Department of Chemistry, Indiana University, Bloomington, Indiana; Division of Metabolic Diseases, Technische Universität München, Munich, Germany
| | - R D DiMarchi
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany; German Center for Diabetes Research, Neuherberg, Germany; Department of Chemistry, Indiana University, Bloomington, Indiana; Division of Metabolic Diseases, Technische Universität München, Munich, Germany
| | - M H Tschöp
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany; German Center for Diabetes Research, Neuherberg, Germany; Department of Chemistry, Indiana University, Bloomington, Indiana; Division of Metabolic Diseases, Technische Universität München, Munich, Germany
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19
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Anandhakrishnan A, Korbonits M. Glucagon-like peptide 1 in the pathophysiology and pharmacotherapy of clinical obesity. World J Diabetes 2016; 7:572-598. [PMID: 28031776 PMCID: PMC5155232 DOI: 10.4239/wjd.v7.i20.572] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Revised: 09/26/2016] [Accepted: 10/18/2016] [Indexed: 02/05/2023] Open
Abstract
Though the pathophysiology of clinical obesity is undoubtedly multifaceted, several lines of clinical evidence implicate an important functional role for glucagon-like peptide 1 (GLP-1) signalling. Clinical studies assessing GLP-1 responses in normal weight and obese subjects suggest that weight gain may induce functional deficits in GLP-1 signalling that facilitates maintenance of the obesity phenotype. In addition, genetic studies implicate a possible role for altered GLP-1 signalling as a risk factor towards the development of obesity. As reductions in functional GLP-1 signalling seem to play a role in clinical obesity, the pharmacological replenishment seems a promising target for the medical management of obesity in clinical practice. GLP-1 analogue liraglutide at a high dose (3 mg/d) has shown promising results in achieving and maintaining greater weight loss in obese individuals compared to placebo control, and currently licensed anti-obesity medications. Generally well tolerated, provided that longer-term data in clinical practice supports the currently available evidence of superior short- and long-term weight loss efficacy, GLP-1 analogues provide promise towards achieving the successful, sustainable medical management of obesity that remains as yet, an unmet clinical need.
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20
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Bodnaruc AM, Prud’homme D, Blanchet R, Giroux I. Nutritional modulation of endogenous glucagon-like peptide-1 secretion: a review. Nutr Metab (Lond) 2016; 13:92. [PMID: 27990172 PMCID: PMC5148911 DOI: 10.1186/s12986-016-0153-3] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Accepted: 11/30/2016] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND The positive influences of glucagon-like peptide-1 (GLP-1) on blood glucose homeostasis, appetite sensations, and food intake provide a strong rationale for its therapeutic potential in the nutritional management of obesity and type 2 diabetes. AIM To summarize GLP-1 physiology and the nutritional modulation of its secretion in the context of obesity and type 2 diabetes management. FINDINGS GLP-1 is mainly synthesized and secreted by enteroendocrine L-cells of the gastrointestinal tract. Its secretion is partly mediated by the direct nutrient sensing by G-protein coupled receptors which specifically bind to monosaccharides, peptides and amino-acids, monounsaturated and polyunsaturated fatty acids as well as to short chain fatty acids. Foods rich in these nutrients, such as high-fiber grain products, nuts, avocados and eggs also seem to influence GLP-1 secretion and may thus promote associated beneficial outcomes in healthy individuals as well as individuals with type 2 diabetes or with other metabolic disturbances. CONCLUSION The stimulation of endogenous GLP-1 secretion by manipulating the composition of the diet may be a relevant strategy for obesity and type 2 diabetes management. A better understanding of the dose-dependent effects as well as the synergistic effects of nutrients and whole foods is needed in order to develop recommendations to appropriately modify the diet to enhance GLP-1 beneficial effects.
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Affiliation(s)
- Alexandra M. Bodnaruc
- School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, 35, University Private, Room 050F, K1N 6N5 Ottawa, ON Canada
- Institut de Recherche de l’Hôpital Montfort, Institut du savoir, 745 Montreal Road, Room 202, K1K 0T2 Ottawa, ON Canada
- School of Nutrition Sciences, Faculty of Health Sciences, University of Ottawa, 35 University Private, Room 050F, K1N 6N5 Ottawa, ON Canada
| | - Denis Prud’homme
- School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, 35, University Private, Room 050F, K1N 6N5 Ottawa, ON Canada
- Institut de Recherche de l’Hôpital Montfort, Institut du savoir, 745 Montreal Road, Room 202, K1K 0T2 Ottawa, ON Canada
| | - Rosanne Blanchet
- School of Nutrition Sciences, Faculty of Health Sciences, University of Ottawa, 35 University Private, Room 050F, K1N 6N5 Ottawa, ON Canada
| | - Isabelle Giroux
- Institut de Recherche de l’Hôpital Montfort, Institut du savoir, 745 Montreal Road, Room 202, K1K 0T2 Ottawa, ON Canada
- School of Nutrition Sciences, Faculty of Health Sciences, University of Ottawa, 25 University Private, Room 116, K1N 6N5 Ottawa, ON Canada
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21
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Fava GE, Dong EW, Wu H. Intra-islet glucagon-like peptide 1. J Diabetes Complications 2016; 30:1651-1658. [PMID: 27267264 PMCID: PMC5050074 DOI: 10.1016/j.jdiacomp.2016.05.016] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2016] [Revised: 05/14/2016] [Accepted: 05/17/2016] [Indexed: 02/06/2023]
Abstract
PURPOSE Glucagon-like peptide-1 (GLP-1) is originally identified in the gut as an incretin hormone, and it is potent in stimulating insulin secretion in the pancreas. However, increasing evidence suggests that GLP-1 is also produced locally within pancreatic islets. This review focuses on the past and current discoveries regarding intra-islet GLP-1 production and its functions. MAIN FINDINGS There has been a long-standing debate with regard to whether GLP-1 is produced in the pancreatic α cells. Early controversies lead to the widely accepted conclusion that the vast majority of proglucagon is processed to form glucagon in the pancreas, whereas an insignificant amount is cleaved to produce GLP-1. With technological advancements, recent studies have shown that bioactive GLP-1 is produced locally in the pancreas, and the expression and secretion of GLP-1 within islets are regulated by various factors such as cytokines, hyperglycemia, and β cell injury. CONCLUSIONS GLP-1 is produced by the pancreatic α cells, and it is fully functional as an incretin. Therefore, intra-islet GLP-1 may exert insulinotropic and glucagonostatic effects locally via paracrine and/or autocrine actions, under both normal and diabetic conditions.
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Affiliation(s)
- Genevieve E Fava
- Endocrinology Section, Department of Medicine, Tulane University Health Science Center, New Orleans, LA, United States
| | - Emily W Dong
- Endocrinology Section, Department of Medicine, Tulane University Health Science Center, New Orleans, LA, United States
| | - Hongju Wu
- Endocrinology Section, Department of Medicine, Tulane University Health Science Center, New Orleans, LA, United States.
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22
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Protein digestion and energy homeostasis: How generated peptides may impact intestinal hormones? Food Res Int 2016. [DOI: 10.1016/j.foodres.2015.12.018] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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23
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Riveline JP, Boudou P, Blondeau B, Gautier JF. Glucagon-secretion inhibition using somatostatin: An old hormone for the treatment of diabetes-associated pancreatectomy. DIABETES & METABOLISM 2016; 43:269-271. [PMID: 27665051 DOI: 10.1016/j.diabet.2016.08.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 08/29/2016] [Indexed: 01/13/2023]
Affiliation(s)
- J-P Riveline
- Assistance publique-Hôpitaux de Paris, Lariboisière Hospital, Department of Diabetes and Endocrinology, DHU FIRE, 75010 Paris, France; University Paris-6, Cordeliers Research Centre, Inserm UMRS 1138, 75006 Paris, France
| | - P Boudou
- University Paris-Diderot Paris-7, Saint-Louis Hospital, Department of Biochemistry, 75010 Paris, France
| | - B Blondeau
- University Paris-6, Cordeliers Research Centre, Inserm UMRS 1138, 75006 Paris, France
| | - J-F Gautier
- Assistance publique-Hôpitaux de Paris, Lariboisière Hospital, Department of Diabetes and Endocrinology, DHU FIRE, 75010 Paris, France; University Paris-6, Cordeliers Research Centre, Inserm UMRS 1138, 75006 Paris, France.
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24
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Kumar DP, Asgharpour A, Mirshahi F, Park SH, Liu S, Imai Y, Nadler JL, Grider JR, Murthy KS, Sanyal AJ. Activation of Transmembrane Bile Acid Receptor TGR5 Modulates Pancreatic Islet α Cells to Promote Glucose Homeostasis. J Biol Chem 2016; 291:6626-40. [PMID: 26757816 DOI: 10.1074/jbc.m115.699504] [Citation(s) in RCA: 94] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Indexed: 12/19/2022] Open
Abstract
The physiological role of the TGR5 receptor in the pancreas is not fully understood. We previously showed that activation of TGR5 in pancreatic β cells by bile acids induces insulin secretion. Glucagon released from pancreatic α cells and glucagon-like peptide 1 (GLP-1) released from intestinal L cells regulate insulin secretion. Both glucagon and GLP-1 are derived from alternate splicing of a common precursor, proglucagon by PC2 and PC1, respectively. We investigated whether TGR5 activation in pancreatic α cells enhances hyperglycemia-induced PC1 expression thereby releasing GLP-1, which in turn increases β cell mass and function in a paracrine manner. TGR5 activation augmented a hyperglycemia-induced switch from glucagon to GLP-1 synthesis in human and mouse islet α cells by GS/cAMP/PKA/cAMP-response element-binding protein-dependent activation of PC1. Furthermore, TGR5-induced GLP-1 release from α cells was via an Epac-mediated PKA-independent mechanism. Administration of the TGR5 agonist, INT-777, to db/db mice attenuated the increase in body weight and improved glucose tolerance and insulin sensitivity. INT-777 augmented PC1 expression in α cells and stimulated GLP-1 release from islets of db/db mice compared with control. INT-777 also increased pancreatic β cell proliferation and insulin synthesis. The effect of TGR5-mediated GLP-1 from α cells on insulin release from islets could be blocked by GLP-1 receptor antagonist. These results suggest that TGR5 activation mediates cross-talk between α and β cells by switching from glucagon to GLP-1 to restore β cell mass and function under hyperglycemic conditions. Thus, INT-777-mediated TGR5 activation could be leveraged as a novel way to treat type 2 diabetes mellitus.
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Affiliation(s)
- Divya P Kumar
- Physiology and Biophysics, Virginia Commonwealth University School of Medicine, Richmond, Virginia 23298 and
| | | | | | - So Hyun Park
- the Department of Internal Medicine, Strelitz Diabetes Center, Eastern Virginia Medical School, Norfolk, Virginia 23507
| | - Sichen Liu
- the Department of Internal Medicine, Strelitz Diabetes Center, Eastern Virginia Medical School, Norfolk, Virginia 23507
| | - Yumi Imai
- the Department of Internal Medicine, Strelitz Diabetes Center, Eastern Virginia Medical School, Norfolk, Virginia 23507
| | - Jerry L Nadler
- the Department of Internal Medicine, Strelitz Diabetes Center, Eastern Virginia Medical School, Norfolk, Virginia 23507
| | - John R Grider
- Physiology and Biophysics, Virginia Commonwealth University School of Medicine, Richmond, Virginia 23298 and
| | - Karnam S Murthy
- Physiology and Biophysics, Virginia Commonwealth University School of Medicine, Richmond, Virginia 23298 and
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Matsuo T, Miyagawa JI, Kusunoki Y, Miuchi M, Ikawa T, Akagami T, Tokuda M, Katsuno T, Kushida A, Inagaki T, Namba M. Postabsorptive hyperglucagonemia in patients with type 2 diabetes mellitus analyzed with a novel enzyme-linked immunosorbent assay. J Diabetes Investig 2015; 7:324-31. [PMID: 27330717 PMCID: PMC4847885 DOI: 10.1111/jdi.12400] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Revised: 06/29/2015] [Accepted: 07/09/2015] [Indexed: 01/11/2023] Open
Abstract
Aims/introduction The aims of the present study were to investigate the performance of a novel sandwich enzyme‐linked immunosorbent assay (ELISA) for measuring glucagon (1–29) with monoclonal antibodies against both the C‐ and N‐terminal regions of glucagon (1–29), and to analyze the differences in plasma levels and responses of glucagon (1–29) to oral glucose loading in normal glucose tolerance (NGT) subjects and patients with type 2 diabetes mellitus. Materials and Methods The cross‐reactivity against proglucagon fragments using the ELISA kit and two types of conventional radioimmunoassay (RIA) kits was evaluated. A 75‐g oral glucose tolerance test was carried out with NGT subjects and patients with type 2 diabetes mellitus, and the glucagon (1–29) concentration was measured using three types of kit. Results The ELISA kit clearly had the lowest cross‐reactivity against miniglucagon (19–29) and glicentin (1–61). The oral glucose tolerance test was carried out with 30 NGT and 17 patients with type 2 diabetes mellitus. The glucagon (1–29) levels measured by the ELISA kit after glucose loading were significantly higher at all time‐points in the type 2 diabetes mellitus group than in the NGT group. However, the glucagon (1–29) levels measured by one RIA kit were significantly higher in the NGT group, and those measured with the other RIA kit were approximately the same among the groups. Conclusions The novel sandwich ELISA accurately determines plasma glucagon (1–29) concentrations with much less cross‐reactivity against other proglucagon fragments than conventional RIA kits.
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Affiliation(s)
- Toshihiro Matsuo
- Division of Diabetes, Endocrinology and Metabolism Department of Internal Medicine Hyogo College of Medicine Nishinomiya Hyogo Japan
| | - Jun-Ichiro Miyagawa
- Division of Diabetes, Endocrinology and Metabolism Department of Internal Medicine Hyogo College of Medicine Nishinomiya Hyogo Japan
| | - Yoshiki Kusunoki
- Division of Diabetes, Endocrinology and Metabolism Department of Internal Medicine Hyogo College of Medicine Nishinomiya Hyogo Japan
| | - Masayuki Miuchi
- Division of Diabetes, Endocrinology and Metabolism Department of Internal Medicine Hyogo College of Medicine Nishinomiya Hyogo Japan
| | - Takashi Ikawa
- Division of Diabetes, Endocrinology and Metabolism Department of Internal Medicine Hyogo College of Medicine Nishinomiya Hyogo Japan
| | - Takafumi Akagami
- Division of Diabetes, Endocrinology and Metabolism Department of Internal Medicine Hyogo College of Medicine Nishinomiya Hyogo Japan
| | - Masaru Tokuda
- Division of Diabetes, Endocrinology and Metabolism Department of Internal Medicine Hyogo College of Medicine Nishinomiya Hyogo Japan
| | - Tomoyuki Katsuno
- Division of Innovative Diabetes Treatment Hyogo College of Medicine Nishinomiya Hyogo Japan
| | | | | | - Mitsuyoshi Namba
- Division of Diabetes, Endocrinology and Metabolism Department of Internal Medicine Hyogo College of Medicine Nishinomiya Hyogo Japan
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Sandoval DA, D'Alessio DA. Physiology of proglucagon peptides: role of glucagon and GLP-1 in health and disease. Physiol Rev 2015; 95:513-48. [PMID: 25834231 DOI: 10.1152/physrev.00013.2014] [Citation(s) in RCA: 286] [Impact Index Per Article: 31.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The preproglucagon gene (Gcg) is expressed by specific enteroendocrine cells (L-cells) of the intestinal mucosa, pancreatic islet α-cells, and a discrete set of neurons within the nucleus of the solitary tract. Gcg encodes multiple peptides including glucagon, glucagon-like peptide-1, glucagon-like peptide-2, oxyntomodulin, and glicentin. Of these, glucagon and GLP-1 have received the most attention because of important roles in glucose metabolism, involvement in diabetes and other disorders, and application to therapeutics. The generally accepted model is that GLP-1 improves glucose homeostasis indirectly via stimulation of nutrient-induced insulin release and by reducing glucagon secretion. Yet the body of literature surrounding GLP-1 physiology reveals an incompletely understood and complex system that includes peripheral and central GLP-1 actions to regulate energy and glucose homeostasis. On the other hand, glucagon is established principally as a counterregulatory hormone, increasing in response to physiological challenges that threaten adequate blood glucose levels and driving glucose production to restore euglycemia. However, there also exists a potential role for glucagon in regulating energy expenditure that has recently been suggested in pharmacological studies. It is also becoming apparent that there is cross-talk between the proglucagon derived-peptides, e.g., GLP-1 inhibits glucagon secretion, and some additive or synergistic pharmacological interaction between GLP-1 and glucagon, e.g., dual glucagon/GLP-1 agonists cause more weight loss than single agonists. In this review, we discuss the physiological functions of both glucagon and GLP-1 by comparing and contrasting how these peptides function, variably in concert and opposition, to regulate glucose and energy homeostasis.
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Affiliation(s)
- Darleen A Sandoval
- Division of Endocrinology and Metabolism, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | - David A D'Alessio
- Division of Endocrinology and Metabolism, University of Cincinnati College of Medicine, Cincinnati, Ohio
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Suzuki K, Jayasena CN, Bloom SR. Obesity and appetite control. EXPERIMENTAL DIABETES RESEARCH 2012; 2012:824305. [PMID: 22899902 PMCID: PMC3415214 DOI: 10.1155/2012/824305] [Citation(s) in RCA: 117] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Accepted: 06/20/2012] [Indexed: 01/01/2023]
Abstract
Obesity is one of the major challenges to human health worldwide; however, there are currently no effective pharmacological interventions for obesity. Recent studies have improved our understanding of energy homeostasis by identifying sophisticated neurohumoral networks which convey signals between the brain and gut in order to control food intake. The hypothalamus is a key region which possesses reciprocal connections between the higher cortical centres such as reward-related limbic pathways, and the brainstem. Furthermore, the hypothalamus integrates a number of peripheral signals which modulate food intake and energy expenditure. Gut hormones, such as peptide YY, pancreatic polypeptide, glucagon-like peptide-1, oxyntomodulin, and ghrelin, are modulated by acute food ingestion. In contrast, adiposity signals such as leptin and insulin are implicated in both short- and long-term energy homeostasis. In this paper, we focus on the role of gut hormones and their related neuronal networks (the gut-brain axis) in appetite control, and their potentials as novel therapies for obesity.
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Affiliation(s)
- Keisuke Suzuki
- Section of Investigative Medicine, Imperial College London, Commonwealth Building, Du Cane Road, London W12 0NN, UK
| | - Channa N. Jayasena
- Section of Investigative Medicine, Imperial College London, Commonwealth Building, Du Cane Road, London W12 0NN, UK
| | - Stephen R. Bloom
- Section of Investigative Medicine, Imperial College London, Commonwealth Building, Du Cane Road, London W12 0NN, UK
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28
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Abstract
Obesity is one of the major challenges to human health worldwide; however, there are currently no effective pharmacological interventions for obesity. Recent studies have improved our understanding of energy homeostasis by identifying sophisticated neurohumoral networks which convey signals between the brain and gut in order to control food intake. The hypothalamus is a key region which possesses reciprocal connections between the higher cortical centres such as reward-related limbic pathways, and the brainstem. Furthermore, the hypothalamus integrates a number of peripheral signals which modulate food intake and energy expenditure. Gut hormones, such as peptide YY, pancreatic polypeptide, glucagon-like peptide-1, oxyntomodulin, and ghrelin, are modulated by acute food ingestion. In contrast, adiposity signals such as leptin and insulin are implicated in both short- and long-term energy homeostasis. In this paper, we focus on the role of gut hormones and their related neuronal networks (the gut-brain axis) in appetite control, and their potentials as novel therapies for obesity.
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29
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McAllan L, Cotter PD, Roche HM, Korpela R, Nilaweera KN. Impact of leucine on energy balance. J Physiol Biochem 2012; 69:155-63. [PMID: 22535285 DOI: 10.1007/s13105-012-0170-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2011] [Accepted: 04/10/2012] [Indexed: 12/14/2022]
Abstract
Body weight is determined by the balance between energy intake and energy expenditure. When energy intake exceeds energy expenditure, the surplus energy is stored as fat in the adipose tissue, which causes its expansion and may even lead to the development of obesity. Thus, there is a growing interest to develop dietary interventions that could reduce the current obesity epidemic. In this regard, data from a number of in vivo and in vitro studies suggest that the branched-chain amino acid leucine influences energy balance. However, this has not been consistently reported. Here, we review the literature related to the effects of leucine on energy intake, energy expenditure and lipid metabolism as well as its effects on the cellular activity in the brain (hypothalamus) and in peripheral tissues (gastro-intestinal tract, adipose tissue, liver and muscle) regulating the above physiological processes. Moreover, we discuss how obesity may influence the actions of this amino acid.
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Affiliation(s)
- Liam McAllan
- Teagasc Food Research Centre, Moorepark, Fermoy, Cork, Ireland
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30
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Whalley NM, Pritchard LE, Smith DM, White A. Processing of proglucagon to GLP-1 in pancreatic α-cells: is this a paracrine mechanism enabling GLP-1 to act on β-cells? J Endocrinol 2011; 211:99-106. [PMID: 21795304 DOI: 10.1530/joe-11-0094] [Citation(s) in RCA: 122] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Proglucagon is cleaved to glucagon by prohormone convertase 2 (PC2) in pancreatic α-cells, but is cleaved to glucagon-like peptide-1 (GLP-1) by PC1 in intestinal L-cells. The aim of this study was to identify mechanisms which switch processing of proglucagon to generate GLP-1 in the pancreas, given that GLP-1 can increase insulin secretion and β-cell mass. The α-cell line, αTC1-6, expressed PC1 at low levels and GLP-1 was detected in cells and in culture media. GLP-1 was also found in isolated human islets and in rat islets cultured for 7 days. High glucose concentrations increased Pc1 gene expression and PC1 protein in rat islets. High glucose (25 mM) also increased GLP-1 but decreased glucagon secretion from αTC1-6 cells suggesting a switch in processing to favour GLP-1. Three G protein-coupled receptors, GPR120, TGR5 and GPR119, implicated in the release of GLP-1 from L-cells are expressed in αTC1-6 cells. Incubation of these cells with an agonist of TGR5 increased PC1 promoter activity and GLP-1 secretion suggesting that this is a mechanism for switching processing to GLP-1 in the pancreas. Treatment of isolated rat islets with streptozotocin caused β-cell toxicity as evidenced by decreased glucose-stimulated insulin secretion. This increased GLP-1 but not glucagon in the islets. In summary, proglucagon can be processed to GLP-1 in pancreatic cells. This process is upregulated by elevated glucose, activation of TGR5 and β-cell destruction. Understanding this phenomenon may lead to advances in therapies to protect β-cell mass, and thereby slow progression from insulin resistance to type 2 diabetes.
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Affiliation(s)
- N M Whalley
- Faculty of Medical and Human Sciences, Manchester Academic Health Sciences Centre, University of Manchester, 3.016 AV Hill Building, Manchester M13 9PT, UK
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31
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Suzuki K, Jayasena CN, Bloom SR. The gut hormones in appetite regulation. J Obes 2011; 2011:528401. [PMID: 21949903 PMCID: PMC3178198 DOI: 10.1155/2011/528401] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2011] [Accepted: 07/25/2011] [Indexed: 12/12/2022] Open
Abstract
Obesity has received much attention worldwide in association with an increased risk of cardiovascular diseases, diabetes, and cancer. At present, bariatric surgery is the only effective treatment for obesity in which long-term weight loss is achieved in patients. By contrast, pharmacological interventions for obesity are usually followed by weight regain. Although the exact mechanisms of long-term weight loss following bariatric surgery are yet to be fully elucidated, several gut hormones have been implicated. Gut hormones play a critical role in relaying signals of nutritional and energy status from the gut to the central nervous system, in order to regulate food intake. Cholecystokinin, peptide YY, pancreatic polypeptide, glucagon-like peptide-1, and oxyntomodulin act through distinct yet synergistic mechanisms to suppress appetite, whereas ghrelin stimulates food intake. Here, we discuss the role of gut hormones in the regulation of food intake and body weight.
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Affiliation(s)
- Keisuke Suzuki
- Section of Investigative Medicine, Imperial College London, London W12 0NN, UK
| | - Channa N. Jayasena
- Section of Investigative Medicine, Imperial College London, London W12 0NN, UK
| | - Stephen R. Bloom
- Section of Investigative Medicine, Imperial College London, London W12 0NN, UK
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32
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Suzuki K, Simpson KA, Minnion JS, Shillito JC, Bloom SR. The role of gut hormones and the hypothalamus in appetite regulation. Endocr J 2010; 57:359-72. [PMID: 20424341 DOI: 10.1507/endocrj.k10e-077] [Citation(s) in RCA: 186] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The World Health Organisation has estimated that by 2015 approximately 2.3 billion adults will be overweight and more than 700 million obese. Obesity is associated with an increased risk of diabetes, cardiovascular events, stroke and cancer. The hypothalamus is a crucial region for integrating signals from central and peripheral pathways and plays a major role in appetite regulation. In addition, there are reciprocal connections with the brainstem and higher cortical centres. In the arcuate nucleus of the hypothalamus, there are two major neuronal populations which stimulate or inhibit food intake and influence energy homeostasis. Within the brainstem, the dorsal vagal complex plays a role in the interpretation and relaying of peripheral signals. Gut hormones act peripherally to modulate digestion and absorption of nutrients. However, they also act as neurotransmitters within the central nervous system to control food intake. Peptide YY, pancreatic polypeptide, glucagon-like peptide-1 and oxyntomodulin suppress appetite, whilst ghrelin increases appetite through afferent vagal fibres to the caudal brainstem or directly to the hypothalamus. A better understanding of the role of these gut hormones may offer the opportunity to develop successful treatments for obesity. Here we review the current understanding of the role of gut hormones and the hypothalamus on food intake and body weight control.
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Affiliation(s)
- Keisuke Suzuki
- Section of Investigative Medicine, Imperial College London, London, UK
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33
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Field BCT, Wren AM, Cooke D, Bloom SR. Gut Hormones as Potential New Targets for Appetite Regulation and the Treatment of Obesity. Drugs 2008; 68:147-63. [DOI: 10.2165/00003495-200868020-00002] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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Chance WT, Sheriff S, Dayal R, Friend LA, Thomas I, Balasubramaniam A. The role of polyamines in glucagon-like peptide-2 prevention of TPN-induced gut hypoplasia. Peptides 2006; 27:883-92. [PMID: 16274854 DOI: 10.1016/j.peptides.2005.09.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2005] [Revised: 09/23/2005] [Accepted: 09/26/2005] [Indexed: 11/23/2022]
Abstract
Total parenteral nutrition (TPN) of rats has been demonstrated to produce hypoplasia of gut mucosa, and to be associated with reduced immune response and elevated translocation of bacteria from gut to mesenteric lymph nodes, spleen and liver. Treatment of rats being maintained on TPN with the proglucagon fragment, glucagon-like peptide-2 (GLP-2), has been shown to totally prevent small intestine mucosal hypoplasia. In the present study, we found that depletion of polyamines with alpha-difluromethylornithine (DFMO) significantly reduced the efficacy of GLP-2 in preserving gut mucosa in rats maintained on TPN for 8 days. Co-infusion of GLP-2 with TPN prevented loss of protein and mucosa in duodenum, jejunum and ileum, but not in colon. Addition of DFMO to the infusate prevented the protective effects of GLP-2 in the duodenum and jejunum. In the jejunum, putrescine and spermidine were reduced in DFMO-treated rats, while the ileum exhibited reductions of these polyamines in rats infused with TPN or TPN plus GLP-2. DFMO infusion further reduced these polyamines in the ileum, while levels of spermine were increased. Concentrations of ornithine decarboxylase were elevated in jejunum of rats infused with TPN or TPN plus GLP-2, but were reduced significantly in DFMO-treated rats. These results suggest that normal levels of polyamines are necessary for the expression of GLP-2-induced hyperplasia. Differential effects of GLP-2 and DFMO across gut segments may relate to regional differences in proliferative and anti-apoptotic effects of the treatments.
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Affiliation(s)
- William T Chance
- Medical Research Service, VA Medical Center, Cincinnati, OH, USA.
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35
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Mahmoodi M, Gardiner JV, Asadi Karam GR, Khaksari M, Murphy KG, Ghatei MA, Bloom SR. Implantation of fibre encapsulated RIN 1056a cells transfected with NPY cDNA into the lateral ventricle of rats alters body weight. ACTA ACUST UNITED AC 2005; 132:80-4. [PMID: 16202459 DOI: 10.1016/j.regpep.2005.09.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2005] [Accepted: 09/08/2005] [Indexed: 11/26/2022]
Abstract
Neuropeptide Y (NPY) is a hypothalamic neuropeptide thought to play an important role in the regulation of food intake and energy expenditure. Our aim was to over-express bioactive NPY in the lateral ventricle by implanting cells transfected with NPY cDNA. Cells from the RIN 1056a clonal rat islet cell line were transfected with NPY cDNA. Radioimmunoassay, chromatography and receptor binding assays were used to ensure the secreted NPY was bioactive, before and after implantation. NPY cDNA transfected and untransfected control cells were encapsulated in PVDF hollow fibres to prevent tumour formation and implanted into the lateral ventricle of male Wistar rats. The effects on body weight and food intake were measured for 15 days. Animals implanted with NPY cDNA transfected RIN 1056a cells showed a greater rise in body weight than controls. This difference was statistically significant five days after implantation, and remained so until the end of the experiment. Cumulative food intake was also increased in rats implanted with NPY cDNA transfected RIN 1056a cells, but this difference failed to reach statistical significance. We have demonstrated that implantation of NPY over-expressing cells into the lateral hypothalamus of rats increases body weight gain.
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Affiliation(s)
- M Mahmoodi
- Department of Biochemistry, Rafsanjan Faculty of Medicine, Rafsanjan, Iran
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36
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Estall JL, Drucker DJ. Dual Regulation of Cell Proliferation and Survival via Activation of Glucagon-Like Peptide-2 Receptor Signaling. J Nutr 2003; 133:3708-11. [PMID: 14608100 DOI: 10.1093/jn/133.11.3708] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Peptide hormones regulate cell viability and tissue integrity, directly or indirectly, through activation of G-protein-coupled receptors via diverse mechanisms including stimulation of cell proliferation and inhibition of cell death. Glucagon-like peptide-2 (GLP-2) is a 33 amino acid peptide hormone released from intestinal endocrine cells following nutrient ingestion. GLP-2 stimulates intestinal crypt cell proliferation leading to expansion of the gastrointestinal mucosal epithelium. Exogenous GLP-2 administration attenuates intestinal injury in experimental models of gastrointestinal disease and improves intestinal absorption and nutritional status in human patients with intestinal failure secondary to short bowel syndrome. GLP-2 also promotes mucosal integrity via reduction of injury-associated apoptosis in the intestinal mucosa and directly reduces apoptosis in cells expressing the GLP-2 receptor in vitro. Hence, the regenerative and cytoprotective properties of GLP-2 contribute to its therapeutic potential for the treatment of patients with intestinal disease.
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Affiliation(s)
- Jennifer L Estall
- Department of Laboratory Medicine and Pathobiology, Banting and Best Diabetes Centre, Toronto General Hospital, University of Toronto, Toronto, Ontario, Canada M5G 2C4
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Bonic A, Mackin RB. Expression, purification, and PC1-mediated processing of human proglucagon, glicentin, and major proglucagon fragment. Protein Expr Purif 2003; 28:15-24. [PMID: 12651102 DOI: 10.1016/s1046-5928(02)00653-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
To examine the cleavage specificity of different members of the furin/propeptide convertase (PC) family of enzymes, we have selected proglucagon (PG) as a model substrate. PG was selected because it is subject to differential processing in vivo. PG is thought to be cleaved initially at an interdomain site to produce glicentin and the major proglucagon fragment (MPGF). These intermediates are subsequently cleaved, most likely by the convertases PC2 and PC1, respectively. To determine the exact sites within PG that are cleaved by PC1 and PC2, we attempted to produce milligram quantities of human PG, glicentin, and MPGF for use in an in vitro conversion assay. A methionine residue was added to the N-terminus of each protein to initiate translation. Purification was achieved using cation exchange and reversed-phase chromatography, and the integrity of the methionylated proteins was confirmed by both electrospray ionization-mass spectrometry and amino acid analysis. The combined expression and purification scheme is fast, efficient, and results in milligram quantities of > or =95% pure proglucagon, > or =95% pure MPGF, and > or =93% pure glicentin. These prohormones are cleaved by PC1 to produce product peptides consistent with the processing of PG observed in vivo, and should therefore be suitable for further analysis of the post-translational processing of PG.
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Affiliation(s)
- Anela Bonic
- Department of Biomedical Sciences, Creighton University School of Medicine, 2500 California Plaza, Omaha, NE 68178-0405, USA
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38
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Jongsma J, Oomen MH, Noordzij MA, Van Weerden WM, Martens GJM, van der Kwast TH, Schröder FH, van Steenbrugge GJ. Different profiles of neuroendocrine cell differentiation evolve in the PC-310 human prostate cancer model during long-term androgen deprivation. Prostate 2002; 50:203-15. [PMID: 11870798 DOI: 10.1002/pros.10049] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND Neuroendocrine (NE) cells are androgen-independent cells and secrete growth-modulating peptide hormones via a regulated secretory pathway (RSP). We studied NE differentiation after long-term androgen withdrawal in the androgen-dependent human prostate cancer xenograft PC-310. METHODS Tumor-bearing nude mice were killed at 0, 2, 5, 7, 14, 21, 47, 84, and 154 days after castration. The half-life of the PC-310 tumor was 10 days, with a stable residual tumor volume of 30--40% after 21 days and longer periods of androgen deprivation. RESULTS Proliferative activity and prostate-specific antigen serum levels decreased to zero after castration, whereas cell-cycle arrest was manifested by increased p27(kip1) expression. A temporary downregulation of androgen receptor (AR) expression was noted after androgen deprivation. The expression of chromogranin A, secretogranin III, and secretogranin V (7B2) increased 5 days after castration and later. Subsequently, pro-hormone convertase 1 and peptidyl alpha--amidating monooxygenase as well as vascular endothelial growth factor were expressed from 7 days after castration on. Finally, such growth factors as gastrin-releasing peptide and serotonin were expressed in a small part of the NE cells 21 days after castration, but strong expression was induced late during androgen deprivation, that is, 84 and 154 days after castration, respectively. CONCLUSIONS Androgen deprivation of the NE-differentiated PC-310 model induced the formation of NE-differentiated AR(minus sign) and non-NE AR(+) tumor residues. The NE-differentiated cells actively produced growth factors via an RSP that may lead to hormone-refractory disease. The dormant non-NE AR(+) tumor cells were shown to remain androgen sensitive even after long-term androgen deprivation. In the PC-310 xenograft, time-dependent NE differentiation and subsequent maturation were induced after androgen depletion. The androgen-dependent PC-310 xenograft model constitutes an excellent model for studying the role of NE cells in the progression of clinical prostate cancer.
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Affiliation(s)
- Johan Jongsma
- Department of Experimental Urology, Josephine Nefkens Institute, Erasmus University, Rotterdam, Netherlands.
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39
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Kieffer TJ, Hussain MA, Habener JF. Glucagon and Glucagon‐like Peptide Production and Degradation. Compr Physiol 2001. [DOI: 10.1002/cphy.cp070208] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Rocca AS, LaGreca J, Kalitsky J, Brubaker PL. Monounsaturated fatty acid diets improve glycemic tolerance through increased secretion of glucagon-like peptide-1. Endocrinology 2001; 142:1148-55. [PMID: 11181530 DOI: 10.1210/endo.142.3.8034] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Diets enriched in monounsaturated fatty acids (MUFA)s have been shown to benefit glycemic control. Furthermore, MUFAs specifically stimulate secretion of the antidiabetic hormone, Glucagon-like peptide-1 (GLP-1) in vitro. To determine whether the MUFA-induced benefit in glycemic tolerance in vivo is due to increased GLP-1 release, lean Zucker rats were pair-fed a synthetic diet containing 5% fat derived from either olive oil (OO; 74% MUFA) or coconut oil (CO; 87% saturated fatty acids; SFA) for 2 weeks. Food intake and body weight gain were similar for both groups over the feeding period. The OO group had improved glycemic tolerance compared with the CO group in both oral and duodenal glucose tolerance tests [area under curve (AUC) 121 +/- 61 vs. 290 +/- 24 mM.120 min, P < 0.05; and 112 +/- 28 vs. 266 +/- 65 mM.120 min, P < 0.05, respectively]. This was accompanied by increased secretion of gut glucagon-like immunoreactivity (gGLI; an index of GLP-1 levels) in the OO rats compared with the CO rats (402 +/- 96 vs. 229 +/- 33 pg/ml at t = 10 min, P < 0.05). Tissue levels of GLP-1 and plasma insulin and glucagon levels were not different between the two groups. To determine the total contribution of GLP-1 to the enhanced glycemic tolerance in OO rats, the GLP-1 receptor antagonist exendin(9-39) (Ex(9-39)) was infused 3 min before a duodenal glucose tolerance test. Ex(9-39) abolished the benefit in glycemic tolerance conferred by OO feeding (OO+Ex(9-39) vs. CO+Ex(9-39), P = NS), and resulted in a deterioration of glycemic tolerance in the OO+Ex(9-39) group when compared with the OO controls (AUC 331 +/- 21 vs. 112 +/- 28 mM.120 min, P < 0.05). To probe the mechanism by which the OO diet enhanced GLP-1 secretion, a GLP-1-secreting L cell line was incubated for 24 h with either 100 microM oleic acid (MUFA) or 100 microM palmitic acid (SFA) and subsequently challenged with GIP, a known stimulator of the L cell. Preexposure to oleic acid but not to palmitic acid significantly increased GIP-induced GLP-1 secretion when compared with controls (55 +/- 12% vs. 34 +/- 9%, P < 0.01). These results demonstrate that the benefit in glycemic tolerance obtained with MUFA diets occurs in association with increased GLP-1 secretion, through a mechanism of enhanced L cell sensitivity. These results suggest that diet therapy with MUFAs may be useful for the treatment of patients with impaired glucose tolerance and/or type 2 diabetes through increased GLP-1 secretion.
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Affiliation(s)
- A S Rocca
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
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Dhanvantari S, Izzo A, Jansen E, Brubaker PL. Coregulation of glucagon-like peptide-1 synthesis with proglucagon and prohormone convertase 1 gene expression in enteroendocrine GLUTag cells. Endocrinology 2001; 142:37-42. [PMID: 11145564 DOI: 10.1210/endo.142.1.7870] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The insulinotropic hormone glucagon-like peptide-1 (GLP-1) is synthesized in the intestinal L cell by prohormone convertase 1 (PC1)-mediated posttranslational processing of proglucagon. Previous studies have demonstrated that proglucagon gene transcription in the L cell is stimulated by the protein kinase A (PKA) pathway through a cAMP response element (CRE). Because the PC1 gene contains two functional CREs, the present studies were conducted to investigate whether the PC1 and proglucagon genes are coregulated by PKA, and to elucidate the temporal relationship(s) of PC1 and proglucagon gene expression with production of GLP-1, in the intestinal cell. The GLUTag enteroendocrine cell line, which is known to express the proglucagon gene and to synthesize and secrete GLP-1, was used as a model. Proglucagon and PC1 messenger RNA transcript levels were both increased after 12 h (but not 24 h) of treatment of GLUTag cells with forskolin/isobutylmethylxanthine (IBMX), by 2.7 +/- 0.3- and 2.4 +/- 0.3-fold, respectively, compared with controls (P < 0.01-0.001). Activation of PKA resulted in a 2.1 +/- 0.1-fold increase in PC1 reporter construct expression (P < 0.001) at 12 h, which was dependent on the presence of the CRE, and a 13- to 24-fold increment in PC1 protein levels (P < 0.01) at 12 and 24 h. Similarly, forskolin/IBMX increased secretion of GLP-1, by 1.8 +/- 0.2- and 2.2 +/- 0.6-fold at 12 and 24 h, respectively (P < 0.05-0.01). Although the cell content of GLP-1 was diminished after 12 h of treatment (P < 0.001), GLP-1 levels increased back to control values after 24 h of forskolin/IBMX treatment (P < 0.01 vs. 12-h levels). Thus, PKA-induced secretion of GLP-1 from the L cell is followed by restoration of the cellular peptide levels through a PKA-mediated, CRE-dependent up-regulation of proglucagon and PC1 gene expression.
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Affiliation(s)
- S Dhanvantari
- Section on Cellular Neurobiology Laboratory of Developmental Neurobiology, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
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Nie Y, Nakashima M, Brubaker PL, Li QL, Perfetti R, Jansen E, Zambre Y, Pipeleers D, Friedman TC. Regulation of pancreatic PC1 and PC2 associated with increased glucagon-like peptide 1 in diabetic rats. J Clin Invest 2000; 105:955-65. [PMID: 10749575 PMCID: PMC377475 DOI: 10.1172/jci7456] [Citation(s) in RCA: 127] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The pancreatic processing enzymes, PC1 and PC2, convert proinsulin to insulin and convert proglucagon to glucagon and glucagon-like peptide 1 (GLP-1). We examined the effect of streptozotocin (STZ) treatment on the regulation of these enzymes and the production of insulin, glucagon, and GLP-1 in the rat. Pancreatic PC1 and PC2 mRNA increased >2-fold and >4-fold, respectively, in rats receiving intraperitoneal STZ (50 mg/kg) daily for 5 days. Immunocytochemistry revealed that, although pancreatic islet cells in the STZ-treated rats were sparse and atrophic PC1, PC2, glucagon, and GLP-1 immunoreactivity increased dramatically in the remaining islet cells. Heightened PC1 and PC2 expression was seen in cells expressing glucagon but not in insulin-expressing cells. Furthermore, in STZ-treated rats, bioactive GLP-1(7-36 amide) accumulated in pancreatic extracts and serum 3- and 2.5-fold, respectively, over control animals. This treatment also caused a 2-fold increase in the ratio of amidated forms of GLP-1 immunoreactivity to total glucagon immunoreactivity in the pancreas but did not affect the ratio of proinsulin to insulin. We conclude that hyperglycemic rats have an increased expression of prohormone converting enzymes in islet alpha cells, leading to an increase in amidated GLP-1, which can then exert an insulinotropic effect on the remaining beta cells.
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Affiliation(s)
- Y Nie
- Division of Endocrinology, Department of Medicine, Cedars-Sinai Research Institute-UCLA School of Medicine, Los Angeles, California 90048, USA
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43
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Affiliation(s)
- T J Kieffer
- Department of Medicine, University of Alberta, Edmonton, Canada.
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Jongsma J, Oomen MH, Noordzij MA, Van Weerden WM, Martens GJ, van der Kwast TH, Schröder FH, van Steenbrugge GJ. Kinetics of neuroendocrine differentiation in an androgen-dependent human prostate xenograft model. THE AMERICAN JOURNAL OF PATHOLOGY 1999; 154:543-51. [PMID: 10027412 PMCID: PMC1850014 DOI: 10.1016/s0002-9440(10)65300-x] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 10/26/1998] [Indexed: 10/18/2022]
Abstract
It was previously shown in the PC-295 xenograft that the number of chromogranin A (CgA)-positive neuroendocrine (NE) cells increased after androgen withdrawal. NE cells did not proliferate and differentiated from G0-phase-arrested cells. Here we further characterized NE differentiation, androgen receptor status, and apoptosis-associated Bcl-2 expression in the PC-295 model after androgen withdrawal to assess the origin of NE cells. PC-295 tumor volumes decreased by 50% in 4 days. Intraperitoneal bromodeoxyuridine (BrdU) incorporation and MIB-1 labeling decreased to 0%, and the apoptosis was maximal at day 4. Androgen receptor expression and prostate-specific antigen (PSA) serum levels decreased rapidly within 2 days. The number of NE cells increased 6-fold at day 4 and 30-fold at day 7. Five and ten percent of the CgA-positive cells were BrdU positive after continuous BrdU labeling for 2 and 4 days, respectively. However, no MIB-1 expression was observed in CgA-positive cells. NE cells expressed the regulated secretory pathway marker secretogranin III but were negative for androgen receptor and Bcl-2. Bcl-2 expression did increase in the non-NE tumor cells. In conclusion, androgen withdrawal leads to a rapid PC-295 tumor regression and a proliferation-independent induction of NE differentiation. The strictly androgen-independent NE cells that were still present after 21 days differentiated mainly from G0-phase-arrested cells.
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Affiliation(s)
- J Jongsma
- Department of Urology, Erasmus University, Rotterdam, The Netherlands.
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Ratineau C, Plateroti M, Dumortier J, Blanc M, Kédinger M, Chayvialle JA, Roche C. Intestinal-type fibroblasts selectively influence proliferation rate and peptide synthesis in the murine entero-endocrine cell line STC-1. Differentiation 1997; 62:139-47. [PMID: 9447708 DOI: 10.1046/j.1432-0436.1997.6230139.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The intestinal epithelium consists of enterocytes, endocrine cells, goblet cells and Paneth cells, which differentiate from pluripotent stem cells located at the crypt bases. The role of the epithelial-mesenchymal inter-actions has been well documented for the differentiation of enterocytes, but the mechanisms that control endocrine cell differentiation are poorly understood. We have cultured the intestinal endocrine cell line STC-1, which synthesizes most of the intestinal peptide hormones, in media conditioned by several subepithelial fibroblast cell lines from three distinct sites of intestine. The fibroblast Swiss 3T3 cell line was used as a non-intestinal control. Our results show that culture media from intestinal fibroblasts inhibit the proliferation rate of STC-1 cells, while those from Swiss 3T3 fibroblasts do not. As regards peptide hormone gene expression, Swiss 3T3-conditioned media have no effect, whereas media from intestinal fibroblasts variably affect cholecystokinin, glucagon, secretin and somatostatin mRNA levels. In particular, clonal subepithelial myofibroblasts do not exert the same effects as mixed subepithelial fibroblasts from homologous intestinal segment. Taken together, these results suggest that cultured fibroblasts of intestinal origin release soluble factors that inhibit STC-1 cell proliferation and modulate, in a region-specific manner, the expression of hormonal peptide genes in this nonspecialized endocrine cell line.
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Affiliation(s)
- C Ratineau
- INSERM Unité 45, Hôpital Edouard Herriot, Lyon, France
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Cheeseman CI. Upregulation of SGLT-1 transport activity in rat jejunum induced by GLP-2 infusion in vivo. THE AMERICAN JOURNAL OF PHYSIOLOGY 1997; 273:R1965-71. [PMID: 9435650 DOI: 10.1152/ajpregu.1997.273.6.r1965] [Citation(s) in RCA: 106] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The effect of in vivo infusion of the peptide hormone glucagon-like peptide 2 (GLP-2) on glucose transport across the rat jejunal brush-border membrane (BBM) was assessed using isolated membrane vesicles. A 2-h infusion of GLP-2 produced a marked acceleration of sodium-dependent glucose uptake into BBM vesicles with a significant overshoot. There was no change in vesicle space or permeability resulting from the hormone infusion. Kinetic analysis showed this stimulation to be the result of a three-fold increase in the maximal rate of transport, with no consistent change in the affinity constant (Km). The time course of this response showed that the effect was observable, but smaller, after only 30 min of hormone infusion and was maximal after 1 h. Sodium-dependent phloridzin binding to the membrane vesicles showed a parallel increase in maximal binding after 1 and 2 h of hormone infusion. Western blotting showed a similar increase in sodium-dependent glucose transporter 1 (SGLT-1) abundance. The effect of GLP-2 could be blocked by luminal brefeldin A or wortmannin. These results indicate that GLP-2 is able to induce trafficking of SGLT-1 from an intracellular pool into the BBM within 60 min and that phosphoinositol 3-kinase may well be involved in the intracellular signaling pathway in this response.
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Affiliation(s)
- C I Cheeseman
- Department of Physiology, University of Alberta, Edmonton, Canada
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47
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Brubaker PL, Crivici A, Izzo A, Ehrlich P, Tsai CH, Drucker DJ. Circulating and tissue forms of the intestinal growth factor, glucagon-like peptide-2. Endocrinology 1997; 138:4837-43. [PMID: 9348213 DOI: 10.1210/endo.138.11.5482] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Glucagon-like peptide-2 (GLP-2) has recently been identified as a stimulator of intestinal epithelial growth, prompting the development of RIA and HPLC methodologies to study this peptide in more detail. A GLP-2-specific antiserum (UTTH-7) was developed that recognizes amino acids 25-30 of human and rat GLP-2-(1-33). UTTH-7 cross-reacts with N- and C-terminally modified forms of GLP-2, proglucagon, and the major proglucagon fragment. Analysis of rat ileal extracts demonstrated the presence of GLP-2-(1-33) as well as significant amounts of GLP-2-(3-33) (16 +/- 7% of total GLP-2). The level of total immunoreactive GLP-2 in plasma from fasted rats was 700 +/- 71 pg/ml, and this increased 3.6-fold (P < 0.001) in 24-h fed rats. HPLC analysis demonstrated the presence of both GLP-2-(1-33) and GLP-2-(3-33) in plasma from fasted rats, with increments in both peptides in plasma from fed rats. Immunoreactive GLP-2 increased in plasma from human subjects 2 h after a meal, rising from 851 +/- 230 to 1106 +/- 211 pg/ml (P < 0.05); 15 +/- 4% of this immunoreactivity was accounted for by the presence of intact GLP-2. HPLC showed the presence of both GLP-2-(1-33) and GLP-2-(3-33) in plasma from fed humans. Incubation of human GLP-2-(1-33) with the enzyme dipeptidylpeptidase IV resulted in liberation of GLP-2-(3-33), whereas replacement of Ala2 with Gly2 prevented this cleavage. Thus, while GLP-2-(1-33) is a major circulating and tissue form of GLP-2, GLP-2-(3-33) is a significant component ofimmunoreactive GLP-2 in both intestine and plasma.
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Affiliation(s)
- P L Brubaker
- Department of Physiology, University of Toronto, Ontario, Canada.
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